Davidson Correction Article Index for
Davidson
Website Links For
Davidson
 

Information About

Davidson Correction




It allows one to estimate the value of the Full Configuration Interaction energy from a limited Configuration Interaction expansion result, although more precisely it estimates the energy of configuration interaction up to quadruple excitations (CISDTQ) from the energy of configuration interaction up to double excitations (CISD). It uses the formula:-

:\Delta \ E_Q = (1 - a_0^2)(E_{CISD} - E_{HF}) \

:E_{CISDTQ} = E_{CISD} + \Delta \ E_Q \

a_0 \ is the coefficient of the Hartree-Fock Wavefunction in the CISD expansion. E_{CISD} \ and E_{HF} \ are the energies of the CISD and Hartree-Fock wavefunctions respectively. \Delta \ E_Q is an estimate of the correction required to estimate E_{CISDTQ} \ , the energy of the CISDTQ wavefunction.


REFERENCE


  • Langhoff, S. R. and Davidson, E. R., ''International Journal of Quantum Chemistry'', 8, 61, (1974)